I have and early S&W 29 serial number S172xxx in nickel it looks to has been re-plated it has a small box stamp under the left grip with a R-N in-side of it. Does anyone know what the stamp stands for?
R-N in the box denotes a Re-nickel done by the factory. There should also be some numbers stamped, like 10.75 which would mean that the Re-nickel work was done the 10th month of 1975.
If the stamp in box was R-B, would mean re-blued.
Is there an N stamped on rear face of the cylinder?
It is factory nickel and could be a re-nickel or a change of finish from bright blue to nickel. If there is no N stamped on the lower left-hand corner of the grip frame, it is the latter.